My husky 128 ld binds up and won't retract the pull cord when I tighten the bolts . Why ?
The answer you seek is impossible to answer except by "who knows!"
The recoil starter is self contained and engages with a shaped boss bolted to the flywheel - assuming everything is original and correctly assembled it should fit without problems, though I usually find a couple of test pulls during the tightening process helps everything bed together.
If it only binds in the last half turn of the retaining bolts a sort of temporary cure would be to fit a flat washer between the starter unit and the air cowl or other housing.
If the starter needs more standoff than a flat washer can provide there is probably something wrong with the assembly.